Qualitative and Quantitative Correlation Study for Exterior Aerodynamics for Automotive Vehicle

The main objective of the external aerodynamic performance assessment of automotive vehicles is to reduce the aerodynamic drag, which improves overall energy consumption of the vehicle. Almost 40% of the energy is required to overcome the drag force offered by the air on the automotive vehicle. With the increase in high performance computing power (HPC) and its affordability, computational fluid dynamics (CFD) has become a popular and more effective tool for aerodynamic design and analysis in the automobile industry. In the real-world scenario, automotive vehicle is subjected to varying wind and operating conditions which affect its aerodynamic characteristics, and therefore it is difficult to reproduce such physical phenomenon in a conventional wind tunnel. Hence, the entire aerodynamic assessment was done in S2A wind tunnel which is equipped with advanced aerodynamic assessment techniques like wheel rotations, boundary layer suction, moving ground etc. The current work mainly focuses on measurement of pressure coefficients through pressure tapings provided on the vehicle rear side and vehicle rear wake structure acquired using tomography method. Computational fluid dynamics has the immense potential of becoming a cost-effective way to achieve such real-world scenario in a virtual environment. Finally, paper summarizes CFD simulation correlation studies with wind tunnel test of the automotive vehicle for drag, pressure coefficients across the various locations and wake structures at vehicle rear side.